Removing obsolete method from channel.h.

This was just glossed over accidentally in a previous CL.

TBR=pthatcher@webrtc.org
NOTRY=True

Review-Url: https://codereview.webrtc.org/2062893002
Cr-Original-Commit-Position: refs/heads/master@{#13114}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 63797930be9121d22ed172cc8fb709475baba97a
1 file changed